You can hide the Genre column, and most others by 'right-clicking' (Control-Command Click) the column heading and deselecting the check mark next to it.
Turning off the iTunes Store in Parental Controls turns off the iTunes Store, not the little arrows that link every element in a song's display line to the iTunes Store.
This little app does what it says, and does it cleanly and easily. (Version 1.1)
LAWRENCEDUDLEY I wrote an app that is both a lot smaller to download than this one and will disable both the iTunes Store links as well as the Genre Browser - it's free of course :-)
It's not as polished looking as this app but it does one (well, two really) things and it does them perfectly well.
Grab it here if you wish: http://www.lawrencedudley.co.uk/my-tunes/ (Version 1.0)